Date-calculating device.



D. s. KERR.

DATE CALCULATING DEVICE.

APPLICATION FILED 13119.4, 1911.

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meager.

Specification of Letters latent.

DATE-CALCULATING DEVICE.

Patented Jan. 5, 19115..

Application filed December a, 1911. Serial No. 663,658.

To all whom it may concern:

Be it"known that 1, DAVID SMITH KERR, ofthe city of Montreal, in theProvince of Quebec and Dominion of Canada, have invented new and usefulImprovements in Date-Calculating Devices, of which the following is afull, clear, and exact specification. '1

This invention relates to improvements in calculating instruments, andthe object is to provide a simple, compact and convenient instrumentwherewith the number of days from one date to another for a period ofone'year may be calculated with great rapidity, and also the days of theweek on which such dates'fall indicated.

firfui'ther object'i's to provide a date calculatin"' instrument of suchform that it may be andled and stored with the greatest ease.

A still further object is to provide a date calculating instrument whichwill be perpetually useful and which will not require supplementarycalculations to be made for lea "years.

orordinaiy purposes, it is not as a rule necessary to calculate the dayof the week on which past dates'fell, but it is very necessary inmanycase's to'determine the day of theweek upon which future dates will falland also to determine the number of days fromo'ne date to another. Thisinformation is'necessary in business and banking houses in order todetermine'whether notes or the likefall due on Sundays, .and also todetermine the number of days between the date of discounting a note andthe due date thereof.

This device consists of a stri of woodor othersu-itable material whichis preferably beveled'at' one edge, and for the purposes of e'ne'ralconvenience inscribed on the bv "with a suitable scale of measurement.Two" groove are formed longitudinally in the ruler body entirely aroundthe same, and these grooves endless ribbons of naetafor other's'uitablematerials are'located. Each these ribbons is divided into 365 equalportions and on one of-these ribbons thedivisions are numbered accordingto the sa s-or the months, while on the other ribbbli 'ih divisionsaremar'ked to indicate theofthe'week. Thecombined front,

nd'ends of the rule are "also divided I v view of the backor bottom into365 parts located so as to register exactly with the divisions of theribbons. ilhese divisions are divided into two columns and numberedaround the rule left to right and right to left from 1 to 365.

In the drawings which ilustrate this invention:-Figure 1 is a plan viewof the top or front of the rule. Fig. 2 is a plan of the rule. :Fig. 3is a cross sectional view. Fig. 4L is an enlarged partial longitudinalsection through one of the ribbon grooves. Fig. 5 is'a View similar toFig. 4 showing a slightly modified form of end. Fig. 6 is a plan view ofone of the supplementary slips used to adapt the day ribbon to allyears.

Referring more particularly to the drawings, 7 designates a strip ofmaterial having a beveled portion 8 at one edge thereof. This edge willbe considered as the front edge, and if the ruler is made of wood thisedge will be provided with a suitable metal reinforcing strip 9. In theapproximate center of the rule 7 a shallow groove 10 is formed in thetop and bogtom of the rule, said groove being contin ous around the endsof the rule. A second similar and preferably narrower groove 11 isformed intermediate the groove 10 and the back edge 12 of the ruler.Endless ribbons 13 and 14 of metal or other suitable material arelocated in the grooves 10 and 11 respectively, the ribbon 13 beinghereinafter referred to as the date ribbon and the ribbon 14 as the dayribbon. Both ribbons are of equal length and are divided into 365 equalspaces designated 15 by means of lines 16 so that the spaces on theribbons can be set in proper alinement. On the date ribbon 13 thesedivisions are numbered for the days of the month, as clearly shown inthe drawings. It will be seen that these numbers 17 are thereforearranged in twelve groups corresponding to the 12 months, the num-v bersextending from 1 to 28 or 30 or 31 in each group, according to the monthwhich it represents. These groups are for convenience indicated bybrackets 18 opposite.

'be obvious that since there are fifty-two weeks and one day in eachyear, then will be two days of the same name appearing together on theribbon, as indicated at the point 21 where two Sundays occur. In orderto enable the ribbons to be shifted with case, each ribbon is providedwith four small pins 22 which are placed at conven ient distances apart.

In order to adapt the day ribbon 14 to all years, I provide small strips23 preferably three in number and of the same material as the ribbon.These strips are each equal in length to seven divisions of the ribbon14, so that the strips may be superposed on the ribbon and cover thespaces of one week. These strips are inscribed on each side with thenames of the days of the week, and each side shows a different dayrepeated. The repeat Sunday is permanently inscribed on the ribbon 14;and one of the strips, for instance that shown in Fig. 6, carries on oneside the repeat Monday and on the opposite side the repeat Tuesday. Thesecond and third strips will carry the repeated Wednesday, Thursday,Friday and Saturday. These strips 23 are adapted to be superposed overthe week containing the repeat Sunday, where they will be held by foursmall pins or other suitable fastening devices 24. The strips not in useare stored in a small recess 25 formed in the bottom of the ruler at oneend thereof, and provided with a suitable sliding cover 26.

The portion of the ruler between-the front edge and the groove 10 isdivided into 365 divisions 27 arranged to exactly register with thedivisions of the ribbon 13.

-It is to be noted thatthese divisions are not all of the same size,there being divisions on the ends of the rule which are larger than thedivisions on the flat surfaces thereof. It is obvious that this must bethe case since the circumference of the ribbons is a trifle less thanthe circumfer ence of the rule. This enlargementof the divisions at theends of the rule is necessary in order that the divisions of the ruleand ribbons may register at all times. In Fig. 4 the rule is shown witha semi-circular end, while in Fig. 5. the upper surface of the rule isbeveled away gradually so that the variation in the size of thedivisions is not so noticeable. In these] two figures the division lines16 are indicated by small notches. These divisions 27 are divided intotwo columns and numbered right to left and left to right from'l to365'inclusive, the 1s of both columns being in the same division. Asshown in the drawings, these divisions correspond on the top-of the rulewith the 1/8 inch divisions of the scale of measurement on the bevelededge 8, but this feature is not at all essential as the divisions may bemade of any size desired. In any case the divisions on the bottom of therule will not register with the scale of measurement owing to the largerdivisions on the ends of the rule, as isshown in Fig. 2.

Arrows 28 are inscribed in both ribbons to indicate the direction inwhich the ribbons should be shifted, although the ribbons can be shiftedin the opposite direction.

Suitable directions may be inserted on the margin of the day ribbon 14as indicated at 29, or may be inserted in the recess 25, givinginstructions for the use of the slips 23.

For convenience of alining the day and date ribbons, the rib 30 betweenthe ribbons is graduated in the same manner as the ribbons themselves.

The instrument is set as follows :J anuary 1 is placed and must alwaysbe kept in alinement with the repeat day. If the date ribbon be movedthe day ribbon should also be moved so that January 1 and the repeat daywill always register.

The instrument is shown set fora year in which the 1st day of Januaryfalls on a Sunday. It is obvious that the number of days between January1st and any date falling within one year may be determined by findingthe day of the month on the date ribbon, and noting the numberinthecolumn next the date ribbon. For instance, from January 1st to December4th is 338 days, both days inclusive, and the latter date falls on aMonday, as indicated by the inscription on the day ribbon in registerwith the date. If it is desired to find the number of days from twodates in the middleof the year, for example, from March 15th to August27th, both inclusive, the date ribbon is moved in the direction of thearrow until March 15th comes opposite the numeral 1 on the rule. August27th is then found on the date ribbon and the number opposite on therule noted, which is 166, this being the required number. In all caseswhere the week day is desired, the repeat day on the day ribbon must beset opposite January 1 on the date ribbon. If both dates are not desiredto be included in the calculation, then deduct one from the total shown.

To adapt the calendar for the following year, the slip 23 containing therepeat Monday would be superposed on the portion of the day ribboncontaining the repeat Sundays and held there by means of the pins 24.The day ribbon is now shifted until the repeat Monday comes oppositeJanuary 1 on the date ribbon.

-- The second column of figures, z. e., the column next the beveled edgeof the ruler, is arranged in reverse order for convenience in reclroninthe number of days expired from a given ate.

As regards leap years, in calculating the number of days from one dateto another into which calculation F-ebruary 29th enters, it would simplybe necessary to take the succeeding number, shown in the colribbon 14:and will repeat day following the one in use on the instrument must beinserted. In other words, the order of the changes would be as follows:On Jan. 1st, 1912, insert repeat Monday; on Feb. 29th, 1912 (leap year)insert repeat Tuesday; on January 1st, 1913, insert repeat Wednesday; onJanuary 1st, 1914, insert repeat Thursday; on January 1st, 1915, insertrepeat Friday; on January 1st, 1916, insert repeat Saturda on February29th, 1916 (leap year), insert repeat Sunday. The day ribbon will showin an ordinary year the day upon which any date from January 1st toDecember 3lst following, both inclusive, falls, and in leap years theday ribbon will show the day upon which any date falls from January 1stto February 28th, both inclusive. After inserting slip 23 on February29th as before explained, the day ribbon will in leap years show the dayupon which any date falls from March 1st to December 31st, bothinclusive.

At all times, the device may be used as a ruler and being thin and flat,is not in the way when lying on a desk. It is also light and easilycarried and operated, the ins 22 in the ribbons serving as a finger -na1catch to enable the ribbons to be easily moved. The slips 23 have thesame flexibility as the therefore move around the end of the rule asreadily as the simple ribbon. It is obvious that this instrument will beof great use to bankingjand business houses where it is constantlynecessary to calculate the number of days-between two given dates, andalso to dete e the day of the week on which a date in the future willfall. These calculations firenece'ssary in de- 29th. On each occa-.

termining interest on accounts, notes, bonds and the like.

Having now what I claim is 1. In a calculating instrument a stationaryscale divided into 365 numbered parts, a movable scale divided into 365parts. and numbered to indicate the days of the month,

fully described my invention,

and a second movable scale divided into 365 parts, and inscribed toindicate the days of the week, and strips adapted to be superimposed ona predetermined portion of the second movable scale, said strips beinginscribed consecutively with thedays of the week from Monday to Saturdayinclusively, one day of each week being repeated.

2. In a calculating instrument a body portion having endless groovesformed therein, an endless stationary scale formed on said body parallelwith the grooves there-,

of, said scale being divided into 365 parts numbered right to left andleft to right from 1 to 365, an endless movable scale arranged in one ofthe body grooves and divided into 365 parts adapted to register with thestationary scale, inscriptions on said movable scale indicating the daysof the month and months of the year, a second endless movable scalearranged in another groove of the'body and divided into 365 partsadapted to register with'the stationary scale and with the first movablescale, inscriptions on said second movable scale indicating the days ofthe week for 52 weeks and one day whereby at one of strips divided tocorrespond with the divisions of the second movable scale, means forreleasably attaching said strips to the second movable scale, saidstrips. havin thereon a series of inscriptions on sai strips, eachinscription indicating the days each having a difierent smm R. w.AIiLltN,

G. M. MonuLANn.

point of the scale a day will be duplicated, a plurality have hereuntoset

